guku0701

i just bought a 2003 w209 clk55 and the AC doesnt seem to cool enough.i live in So cal so it gets pretty hot.i refilled with refrigerant but no difference.i took it to a shop and they found out its blowing 44F and its normal according to them.but this is just not enough.when its 90F out it doesnt get cold enough to the point im comfortable.My GF beetle has much cooler AC compared to mine.please help its getting really hot here.the ac turns on fine and works fine too but its just not blowing cold enough.these are the codes i found doing the test

1. 73
2. 67
3. 46
4. 46
5. 48
6. 203
7. 18
8. 118

City Rat

Sadly not much help to you but I am having a similar problem with my 02 CLK55. When it is cool in the morning it blows cold air but in the afternoons when it gets in high 90s or yesterday 100, it was hotter with the ac on in the car than it was driving with the windows rolled down. Imagine it was a relief to roll down the windows on a 100 degree day. I was about to buy refrigerant when it was blowing nice and cold again this morning.

guku0701

i have a similar case but mine gets a little cold.still not enough.you might want to read the codes like i did above but thats all i can tell you with my knowledge.

GatorMB

The Mercedes is from Europe where climates are a bit different than the US. Volvo always had a bad AC but a good car for the same reason.
The heater is always circulating hot water and the recirculation button is on a timer for safety reasons.
With hot water always circulating next to the evap, The Freon will have to work harder to remove heat.
Recirculation is like your house, taking cool air and making it colder. The Benz times out and reverts to fresh 100^ air. Humidity is the killer here in the US as Europe does not exhibit these temp extremes coupled with humidity.
Other factors contribute to poor cooling like oil saturation and moisture contamination from leaks will effect the refrigerants abilities to remove heat.

I am not knocking anyones opinion of the CCS, Europe or anyone else but I have lots of windshield time in on many of these cars in Florida and brother it is smooookin hot.
Mono valve and hot water recirc systems will fail and cause many of the symptoms reducing the cooling.

Gator

City Rat

Gator,
Understood but MBZ has been exporting cars to the USA and ME for decades now. One would think that they would have worked through this issue now in later model years. Have they? Even other product lines, like cLS, SL, SLK, E, etc. Haven't they? If not what ate the work atounds that people have tried, bigger condensors, evaporators, etc.

GatorMB

You Bet,
AC will work anywhere, Death Valley, Middle East, Florida and South America. Just not as well at certain times of the year.
I have been working on mine today pulled my back out reaching for the ETC sensor.(evap) The sensor reading's above look favorable.
#5- 48^ supply air is a working system. #1- in car reports 73^. Cool but not cold, Window tint might mask the extra heat, and use recirculation moderately after a time out. Other factors might be the internal dampers not directing the cold air properly.
Heat door hanging up with a comb or lighter some debris. etc..

Don't know if guku is a cab or not but that introduces more cooling issues.
The both of you might need topping up on refrigerant, The sensors readings are not a true gage reading from an AC manifold that I would use to review AC refrigerant problems.
#7 is a pressure sensor showing 18, most systems will not turn on with 18 psi.

Volvo used to use a copper core evap for some time and they outlasted the car in some cases. The copper takes a lot longer to transfer heat than aluminum. The aluminum cools better by transferring heat faster but is easily internally damaged by moisture contamination. In Florida the copper was never efficient enough to keep the cabin ice cold in extreme summer.
The Mercedes Climate Control System introduces hot water into the car any time the temp selected is above Low or defrost. It is very difficult for the AC in any automotive system to overcome hot water in extreme climates.
Hang some gages on that system and we can see what is going on.

Gator

City Rat

Clearly the easiest and cheapest first step. That will get done this week. Will report back.

guku0701

thanks gator.are you saying that i dont have enough refrigerant pressure?i found out from other sourced that it was plenty and i have also refilled my ac last month but found no change in results at all.by the way mines a coupe.what would you suggest for this situation?sorry i took long to reply.